Aramid polymer and powder filler reinforced elastomeric composition for use as a rocket motor insulation

Abstract

An elastomeric composition suitable for use as a rocket motor case insulation is disclosed. The composition consists of a vulcanizable elastomeric composition and reinforcing aramid polymer fibers in combination with a powder filler. A preferred embodiment utilizes polyisoprene as the elastomer, KELVAR TM fibers as the aramid polymer fibers, and silica as the powder filler.

What is claimed is: 
     
       1. A process for insulating a solid propellant rocket motor, comprising the step of employing an essentially asbestos-free elastomeric composition as an insulating liner, said composition comprising: A. from 1 to 40 percent by weight of aramid polymer fibers,   B. from 1 to 75 percent by weight of a powder filler selected from the group consisting of silica, iron oxide, titanium oxide, carbon, milled glass, and ceramic clays, and   C. A vulcanizable elastomeric composition including: (i) a vulcanizable elastomer, and   (ii) vulcanizing agents for said elastomer.     
     
     
       2. The process of claim 1 wherein the aramid polymer fiber content ranges from 17 to 28 percent by weight. 
     
     
       3. The process of claim 1 wherein said vulcanizable elastomer is polyisoprene. 
     
     
       4. The process of claim 1 wherein said powder filler is composed of particles having an average particle size of at least 30 millimicrons. 
     
     
       5. The process of claim 1 wherein said vulcanizable elastomer is polyacrylonitrile rubber. 
     
     
       6. The process of claim 1 wherein said vulcanizable elastomer is butyl rubber. 
     
     
       7. The process of claim 1 wherein said vulcanizable elastomer is a butadiene-styrene copolymer. 
     
     
       8. The process of claim 1 wherein said vulcanizable elastomer is nitrile rubber. 
     
     
       9. The process of claim 1 wherein said vulcanizable elastomer is polybutadiene. 
     
     
       10. The process of claim 1 wherein said vulcanizable elastomer is silicone rubber. 
     
     
       11. The process of claim 1 wherein said vulcanizable elastomer is chlorosulfonated polyethylene. 
     
     
       12. The process of claim 1 wherein said vulcanizable elastomer is a fluorocarbon polymer. 
     
     
       13. The process of claim 1 wherein said vulcanizable elastomer is an ethylene-propylene diene monomer. 
     
     
       14. The process of claim 1 wherein said vulcanizable elastomer is a polysulfide. 
     
     
       15. The process of claim 1 wherein said vulcanizable elastomer is neoprene. 
     
     
       16. The process of claim 1 wherein said vulcanizable elastomer is a polyurethane. 
     
     
       17. The process of claim 1, wherein said powder filler is silica. 
     
     
       18. A process for insulating a solid propellant rocket motor, comprising the step of employing an essentially asbestos-free elastomeric composition as an insulating liner, said composition consisting essentially of: A. from 1 to 40 percent by weight of aramid polymer fibers;   B. from 1 to 75 percent by weight of powder filler selected from the group consisting of silica, iron oxide, titanium oxide, carbon, milled glass, and ceramic clays; and   C. A vulcanizable elastomeric composition including (i) a vulcanizable elastomer, and   (ii) vulcanizing agents for said elastomer.     
     
     
       19. The process of claim 18, wherein said powder filler is silica.